Coronavirus Scotland: Explaining how the west of Scotland ended up back in lockdown

At one point during this period, cases detected in people aged 18 to 24 accounted more than 40 per cent of all new Covid infections in Scotland.

"There's no question that the universities returning created an issue,” said Professor Linda Bauld, who is now spearheading efforts to mass test around 9000 students at Edinburgh University to enable them to return home safely for the festive holidays.

READ MORE: How did we end up back in lockdown? Follow the data

She and other public health experts remain baffled that the Scottish Government failed to follow through on the recommendations of its own scientific advisors to mass test students back in September, amid clear international evidence that asymptomatic spread in shared accommodation was a major danger.

"Some of the English universities did do it," said Prof Bauld. "Cambridge has got a great testing programme where their students can be tested every week, they have 80% uptake of that programme. The University of East Anglia did it.

“But none of the Scottish universities did.

"At Edinburgh there was one of our labs that could have assisted with that programme, but that wasn't taken forward."

Prof Bauld, the Usher chair of public health at Edinburgh University, added that Test and Protect “has not been working the way we would wish” after revised data revealed that up to 36% of cases during September were taking contact tracers more than 72 hours to complete.

This is the time between being notified of a positive case, interviewing them, and advising all their close contacts to self-isolate.

Around a third of cases in September were taking contact tracers more than 72 hours to close

UK SAGE warned back in May that “any delay beyond 48-72 hours total before isolation of contacts results in a significant impact on R” – in other words, allowing transmission of the virus to rapidly accelerate.

On October 7, Scotland’s test positivity rate broke through the 5% barrier for the first time – the measure used by the World Health Organisation to gauge whether an outbreak is beginning to spread out of control.

Britain, as an island, was also in a prime position to tighten borders and impose strict quarantines on travellers as Covid success stories such as Taiwan and New Zealand have done.

While holidaymakers returning to Scotland from areas of high prevalence were required to self-isolate there were few checks, with only 12% ever spoken to by contact tracers.

“Keeping borders tightly controlled is key and then trying to rely on your first line of defence which is testing, tracing and isolating, but you need the population to be compliant,” said Professor Igor Rudan, an expert in international health at Edinburgh University.

"You really cannot have loopholes in this system. But they do allow a reasonable quality of living. The countries of Taiwan, Singapore and Japan or China, they have all demonstrated that this is possible for a long period of time.

"Australia are also trying something similar now. I think that in Europe we are not seeing these success stories so clearly.

"We are reluctant to impose such stringent orders. It is entirely against the political thought of Europe, which is 'without borders'.

"The politicians don't seem to think that their populations would stand such stringent measures of control and surveillance for a long time."

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Professor Rowland Kao, a mathematical biologist who specialises in infectious disease dynamics, added: "We almost certainly came very close to eradicating [Covid] in Scotland this summer – unfortunately, unless you have very tight controls on people coming into Scotland that is almost impossible.”

Without these, Prof Kao says he would have “slowed down” on allowing higher risk events, such as hospitality, which allow large numbers of people to gather in the same indoor space.

“My view is that the ‘circuit breaker’ approach with phased on and off periods - not just one, but repeated ones - would be better in allowing some normalcy but keeping things under control.

“Sometimes with very strict controls, others with more relaxed ones.”

In recent days the decline in hospital admissions for Covid (top) has levelled off, while ICU admissions for Covid have increased (Public Health Scotland data to November 16)

The timing of Level 4 restrictions has been couched in terms of relieving pressure on hospitals and urgently reducing Covid cases in areas where the prevalence of the virus has remained “stubbornly high”.

In Greater Glasgow and Clyde, its quota of 45 intensive care beds had run out by Wednesday with 52 Covid and non-Covid patients requiring critical care.

The health board can resort to creating a ‘surge capacity’ of up to 170 ICU beds, but this requires diverting space and staffing from other parts of its hospitals.

During the first wave, operating theatres across the NHS were converted into temporary ICUs and hundreds of staff redeployed to intensive care, but this was facilitated by the blanket suspension of elective procedures.

Forth Valley had two ICU beds left as of Wednesday before surge capacity would be required, while Lanarkshire and Ayrshire were already using 50-60% of their maximum.

Dr John Thomson, vice president of the Royal College for Emergency Medicine in Scotland, said: "Despite the Level 3 restrictions, the Glasgow and Lanarkshire areas, and to a lesser extent Ayrshire, are under significant strain and pressure at the moment in terms of Covid and general hospital capacity.

“From an emergency department perspective, in the last week in particular we've seen long waits for patients who need admitted to hospital and in some departments patients being on trolleys all night waiting for beds.”

READ MORE: Doctors claim self-isolation rules 'being fudged' to avoid staff shortages 

He said there were growing concerns about ambulances “stacking” outside A&E’s – where the vehicles have to queue up with patients on board because there is no space to bring them in.

“That's not particularly new for the Queen Elizabeth in Glasgow, but for other hospitals in the country that's never happened before," said Dr Thomson.

"In the past they would have put them in the corridor - not that that was acceptable, but that was the norm.

“From an infection prevention and control point of view that's no longer acceptable, but it means there's no clinical space to put patients.”

Nonetheless, the spread of Covid within hospitals has caused growing alarm in recent weeks.

Official statistics show that the number of patients who had ‘probably’ or ‘definitely’ contracted the virus while in hospital (based on positive specimens collected eight or 15 days after admission) doubled last month, from 94 in the week ending October 11 to 189 in the week ending October 25.

Hospital-acquired Covid accounted for 2% of the infections nationally.

Cases of hospital-acquired Covid increased notably during October

There is no data yet for November, but reports have emerged on Covid and non-Covid patients being placed on the same wards as beds ran out and of medical staff struggling to socially distance in shared spaces, such as changing rooms and canteens, exacerbating the risk of staff outbreaks.

“The strain we're seeing is in the general medical beds,” said Dr Thomson.

“One of the factors of the second wave has been the rate of nosocomial [hospital-acquired] infections that has impacted significantly on the number of beds that are available and indeed the staff available, because there is a significant number of staff who either have Covid or are self-isolating due to hospital spread.

"The main issue at the moment isn't critical care, it's general hospital capacity.”

The pressure is now on to drive down the virus in time for Christmas relaxations – even if that means a spike in cases come January.

The plans are yet to be confirmed for Scotland, but UK ministers are reportedly looking at ways to allow three or four households to mix indoors for five days over Christmas in England.

SAGE advisors have warned this may have to be offset by 25 days of tougher restrictions come January, with tens of thousands of extra cases "quite plausible" according to Cambridge University statistician and risk expert, Professor Sir David Spiegelhalter.

Prof Kao said: “Christmas is a huge wildcard. Between moving people around to different places, possible reductions in quarantine for international travel, a combination of probably mildly or asymptomatic younger people mixing with friends and mixing with family - especially older relatives - plus colder, wetter weather. It is a concern yes.

“Hopefully, there are good plans in place for after Christmas, with people bringing infection back from wherever they’ve been.

“However, if we can drive down the infection numbers to a very low level beforehand, have clear rules and approaches, that’ll be the best chance to have something like a ‘normal’ Christmas.”